Current street lights operating on an alternating current (AC) power source only have the ability to turn on and off. In other words, the street lights operating on AC power cannot be dimmed to some level of brightness in between an on and off state.
Current street light fixtures only provide a receptacle for receiving a three pronged connector. Some dimming controls exist, but would require a receptacle for receiving a five pronged connector. As a result, all existing street light fixtures would need to be modified, which may be prohibitively time consuming and expensive.
Alternatively, street light fixtures may be modified internally. However, such modification may void the manufacturer's warranty on the street light fixture. In addition, the street light fixture may not provide enough space for all of the components that would be required to provide dimming control.
Other methods for dimming AC powered lights include converting the AC power into direct current (DC) power, adjusting the power and then re-converting the DC power to AC power before it is delivered to the street light fixture. However, this method is inefficient. In addition, this method would require additional hardware modules to perform the conversion. The additional modules may not fit in a photocontroller module used to control the street light fixture.